Cooling device for telephone-transmitters for strong current.



c. E. EGNE IR & J. G. HOLMSTRUM. COOLING DEVICE FOR TELEPHONETRANSMITTERS FOR STRONG CURRENT.

APPLICATION FILED MAR.26, 1910.

Patented July 29, 1913.

3 SHEETS-RESET 1.

Even/$7- G. E. EGNER & J. G. HOLMSTROM. COOLING DEVICE FOR TELEPHONETRANSMITTERS FOR STRONG CURRENT. APPLICATION FILED MAR. 26, 1910.

1,068,871. Patented July 29, 1913 3 SHEETS-SHEET 2.

0. B. E'GNE'R & J. G. HOLMSTRb'M. COOLING DEVICE FOR TELEPHONETRANSMITTERS FOR STRONG CURRENT.

APPLICATION FILED MAR.26,1910.

Patented July 29, 1913.

3 SHEETS-8111131 3.

'4 5 0000 OGUO Even/Z5 7%; W WW fq ww Zne 51966 UNITED STATES PATENTorator.

CARL EMIL EGNERjOF S TOGKHOLM, AND JOHAN GUNNAB, HOLMSTBM, $AL'1SJ6-sroalinenn, .swn'nniv.

COOLING DEVICE FOR TELEPHONE-TRANSMITTERS FOB. STRONG CURRENT.

Specification of Letters Patent.

Patented July 29, 1913.

Application filed March 26, 1910'." Serial 110 551588.

specification,'rejference being had therein to accompanying drawings.

This invention relates to cooling devices for telephone transmitters forstrong current, which transmitters are used in" such cases when aspecially forcible action of the transmitter is necessary. Thecharacteristic feature of the 1nvent1on consists 'in the cooling mediumbeing inclosed in a receptacle, with the bottom part of..which thetransmitter is so connected, that, at the heating of the cooling medium.effected by the medium absorbing the heat generated in the transmitter,circulation of the medium is effected, by the heated part. of j the sameascending in the receptacle, and the cooler part passing in oppositedirection. Consequently the cooling device acts entirely automatically.Accordmg to one form of execution of the invention a solid body oflow-melting-point, for instance parafiln or an alloy, is used ascoolingmiedium. In

such case the cooling is efi'ected substantially by the enerated heatbeingused for melting the sai body.

In the accompanying drawings Figure 1 shows in vertical section a formof execution of the invention. Figs. 2 and 3 show in a vertical sectionand a plan view a receptacle for the cooling medium adapted especiallyfor a solid body of low melting point as cooling medlum. Flgs. 4.and 5show in vertical sections two further forms of execution of theinvention.

In Fig.1 carbon granules 3 are provided between theelectrodes 1 and 2.The electrode -1"-consists of two concentric parts,

fixedto the bottom of a tube 4 and insulated from each other. The outerpart is insulated also from the said tube 4. The electrode 2 issupported by athin ring 5 preferably of steel, which ring is connectedwith a diaphragm 6, which is stretched outward from its center bysuitable means,jnot described, as they form no part of this invention.The electrode 2 and the ring 5 are firmly forced against the '1diaphragm by means of a screw bolt Tandnuts 8.. Still disks 11, 11- ofsteel, mica, or thelike are located between the said nuts 8 and thediaphragm and between the ring 5 and the diadphragm. The ring 5, thescrew bolt 7 an the nuts 8 are insulated from the'diaphragni 6. A ring 9of felt or the like in-- closes the electrode 2 and prevents the carbongranules 3 from falling out. Over the said ring 9 a thin ring-shapeddisk 10,- preferably of mica, is located, which partially covers theamount of carbon granules and prevents the electric current from passingthrough the granules located nearest to the ring 9. Owing to. the saidarrangement the said ring will not be heated by the current and spoiledby the same.

The tube 4; extends upward and" forms a receptacle or cup partially openat its top and containing the cooling medium, water for instance. Theheat enerated by the current passing through t e electrodes, isconducted by the electrode 1 and partially by the air located above thesaid electrodeto the tube 4 and, after the heat has passed through thewall of the said tube, it is ab sorbed by the water. In the tube 4 theheated part of the water ascends, while the cooler part passes inopposite direction, circulation in. the tube being thus .efiected andthe generated heat continuously absorbed. When the temperature of thewater has reached a kind of equilibrium, which is dependent ofthestrength'of the current used andfthe period durmg WlllCllconversation is going on, the said state is maintained by radiation ofheat as well as by heat being absorbed owing to the evaporation of thewater. Consequently, the advantage of the cooling device consist-stherein that it operates automatically and with a constant orsubstantially constant'quantity of cooling medium,

no means for leading the medium to and from the device or for changingthe same continually being thus necessary as in cooling devices beforeused, which means make the construction of the transmitter complicatedand expensive.

The diaphragm of the transmitter is located below the transmitter. Thisis an advantage because the heat generated between the electrodes causesacurrent of hot air to ascend, which would heat the diaphragm if locatedabove the electrodes. The transmitter has a mouth 12, the bottom wall 13of which forms an angle of to the center line of the transmitter andconse quently throws the sound waves upward toward the diaphragm. Thetransmitter is provided with contact screws 14, 15, 16 connected withthe tube 4, the outer part of the electrode 1 and with the ring 5respectively.

Owing to the said arrangement the electrodes may be ,so coupled, thatthey form two transmitters connected either in series or in parallel.

'In order to adjust the pressure between the contacts of the transmitterby moving the electrode 1 into a position nearer to or farther from theelectrode 2 in the well known manner, an adjusting mechanism is providedat the top end of the transmitter, by means of which the tube 4, guidedin any suitable manner, in the casing 17 of the transmitter, with theelectrode 1 can be raised or lowered. The said adjusting mechanismconsists of a screw bolt 18 fixed in the tube 4 and movable in thecasing 17 of the transmitter and provided with nuts 19 and 20. A spring21 acts upon the tube 4 tending to move the same downward.

Instead of water or any other cooling liquid a solid body may be used,which can be brought. into a melted state at a low temperature, forinstance paraffin or an alloy of tin, lead and bismuth. The heatgenerated in the transmitter will be absorbed, while the said body isheated to the .melting point and then is brought into the melted state.By using a body of suitable melting po nt and in a suitable uantity,adapted to the amount of heat which is to be absorbed, the temperature,at which the contacts of the transmitter operate, can be kept at themost suitable degree. If the tube or receptacle is sufliciently greatand contains a sufficient quantity of the said body, its coolingcapacity, after the body has been brought into the melted state, neednot at all be used. All heat, which is to be absorbed and is not carriedoff directly, will be used for the melting operation. As now,

as well known, the temperature of a melting body remains constant aslong asany part of the body is unmelted, it will be possible to malntainconstant the temperature of a transmitter, cooled by means of a meltlngbody, as long as the transmitter 18 used for a conversat1on,-wh1chgenerally is for a short time only, and consequently the transmitteritself are shown. 3 are the carbon granules located betweentheelectrodes 1 and 2, and 9 is the ring of felt or the like, 21 is theparaflin provided in the tube 4. According to these figures wires 22,pipes, strings or the like of copper or any other material of great heatconducting ca pacity are located in the tube, extending upward from itsbottom. The said wires are fixed preferably in' a layer 23 of tinforming a metal connection with the bottom of the tube 4.- The heatgenerated at the electrodes is conducted through the bottom and the sidewall of the tube-4 to the wires 22 and the paraflin. A small amount ofthe heat is absorbed by the heating and melting of the parafiin at thebottom of the tube 4. The greatest part of theheat, however, isconductedfarther upward through the wires 22. Owing to the greatcontactsurface between the wires and the paraflin a great part of theparafiin'will be brought into a melted stateu If the distance betweenthe wires 22 is short, the whole mass of paraflin will absorb the heatalmost uniformly. vVires of copper conduct the heat a hundred times morerapidly than solid paraffin. Consequently it is easily understood thatthe cooling device just described is exceedin ly more effective than theone described a ove, in which the tube contains only parafiin or a bodyhaving a slight heat reliable manner through the melting of theparaflin, which is generated at the electrodes during the generallyshort period conversation is going on. and the said heat can have noinjurious influence upon the transmitter and its diaphragm. The wires 22may be cylindrical, as shown. or flat, corrugated,

fluted or arranged in any other suitable manner in order that theirsurface may be great at the same time as their weight is slight. Thewires must not necessarily be straight. For the purpose in questionirthe electrode 1 fixed to the same.

regular wires of copper have been used with a favorable result, the saidwires being forced into the tube 4 and the paraiiin then poured into thesame in a melted condition.

6 is the diaphragm, which in this form of execution is located above theelectrode.

'The electrodes 1 and 2 are both single and the lower one is cooled. Thecooling liquidis contained in a special cup 24, located out side thetube 4 and connected with the same. The electrodes 1 and 2 are providedat the bottom of the said tube. Also in this transmitter there is acirculation of the water caused by the heat absorbed from thetransmitter. The cup 24 is provided with an in- .let pipe 25 and anoutlet pipe 26 for the liquid, so that the liquid in the cup can bechanged. Air .pipes 27 extend from the outer side of the cup 24 to thechamber of the tube 4, thus permitting cold air to pass into the saidchamber. Also in this form of execution the pressure of the electrodesagainst the carbongranules is adjusted by raising or lowering the liquidreceptacle and For the said purpose the electrode 1 has a hollow pin 28-extending downward and tightly connected with thereceptacle 24. The saidpin is guided by a sleeve-29 in the frame of the transmitter. A piece 30is fixed in the pin 28 and pins 31 screwed into the said piece extendthrough longitudinal slots 32 provided in the sleeve 29. A spring 33hearing against the frame and the pins 31 tends to move the receptacle24 andthe electrode 1 downward. Adjustment is efiected by means of ascrew bolt 34 provided with a handwheel 35 and in screw-threadedengagement with a cover 36 screwed on the sleeve 29.

The said, bolt 34 bears against the piece 30.

In Fig. 5 an apparatus is shown, in which two (or more) transmitterscooperate with the same diaphragm. Forthe rest the apparatus is arrangedin'substantially the same manner as in Fig. 1. The electrodes 2 arefixed to and insulated-from a common disk 37, which is firmly connectedwith the dia, phragm' 6 by means .of a screw bolt 38 with a nut 39, anda ring 5 of steel or the like. The cooling tubes 4, each supporting anelectrode 1 and acted upon downward by a spring 21 can be raised andlowered by means of a screw bolt 18 with nuts 19, 20. v The said screwbolts are carried by an arm or a disk 40 extending from a sleeve 41,sliding on an upright 42, fixed in the casing of thetransi'nitter. Aspring 43 acts upon thesleeve 41 upward and the sleeve can be raised orlowered by means of nuts 44, 45 onthe upright 42. Owing to the saidarrangements the transmitters can be adjusted separately and jointly.Owing to the fact that the cooling device accompanies the electrodeswhile being adjusted, which is the case also in the transmitters shown.in Figs. 1 and 4, the construction of the transmitter is simplified inan essential degree. The transmitters are insulated from each other andfrom the casing and provided with contact screws 14, 15, 16, by. meansof-.which the transmitters can be connected in series or in parallel.The tubes 4 are also insulated from each other in a suitable manner, sothat the current can not pass throughthe cooling liquid from one of thetransmitters to the other. In multiple transmitters hitherto used thesaid passage of the current only with great difl'iculty has beenprevented.

Transmitters of the type shown in Fig. 4

may evidently be combined in the same manner as in the transmitter shownin Fig. 5 to cooperate with a common diaphragm.

Having now described our invention, what we claim as new and desire tosecure by Letters Patent is: Y 1

1. In a telephone transmitter for strong current, electrodes, areceptacle located with its bottom in the vicinity of the electrode fromwhich heat generated by the current is derived and a body ofcoolingmedium held permanently in the receptacle for absorbing the heat.

2. In a telephone transmitter for stro1 1g current, electrodes, areceptacle havlng Its bottom connected with the electrode from -whichheat generated by the current is derived, a body of cooling mediuminclosed in the said receptacle and means for raising and lowering thesaid receptacle for adjusting the pressure of the electrode against thecontacts cooperating with the same.

3. In a telephone transmitter for strong current, electrodes, a tubehaving its bottom connected with the electrode from which heat generatedby the current is derived, a body of cooling medium held within thetube, a fixed support and means connecting the tube with the fixedsupport for adjusting the tube and hence the electrode'against thecontacts codperatingwith the same.

. 4. In a telephone transmitter for strong current, a diaphragm, aplurality of transmitter cells cooperatin with the said diaphragm, acorresponding number of in sulated receptacles each connected at itshottom with one of the electrodes of the respecsigned our names in the'presence of two. subtiye cells and containlng a cooling medium, scribingwitnesses.

means for raising andlowering each of the (EARL EMIL EGNER. Y saidreceptacles and the electrode connected 'JOHAN GUNNAR HOLMSTMM.

therewith and vmeans-for raising and lower- Witnesses:

ingthe said receptacles sirr'mlt'anmiusly. HEDVIG VMELINDER,

In witness whereof, we have hereunto ROBERT APELGREN.

